Slot apparatus for memory module

ABSTRACT

A slot apparatus for a memory module on a printed circuit board. The slot apparatus includes a first memory slot set, a second memory slot set, a terminal resistor, and a serial resistance. The first and second memory slot sets are disposed on the printed circuit board. The terminal resistor is disposed between the first and second memory slot sets. The serial resistance is disposed on the printed circuit board and is electrically connected to the first and second memory slot sets through the printed circuit board. The terminal resistor is respectively and electrically connected to the first and second memory slot sets through the printed circuit board. The terminal resistor and the first and second memory slot sets are connected to a terminator voltage.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motherboard, and in particular to aslot apparatus for DRAM memory module.

2. Description of the Related Art

Digital information is often stored in dynamic random access memory(DRAM). One type of DRAM transfers information synchronously with aclock signal. This type of DRAM is referred to as synchronous DRAM(SDRAM). SDRAM provides a burst read access (when programmed for a burstlength of 4). In the case of 64-bit data bus interface system, such atransfer involves 32 bytes of data per SDRAM access. Current PC systems,for example PC100 or PC133 systems typically use such an arrangement.SDRAM transfers information once during every cycle of the clock signal,for example, at the rising edge of the clock signal. Double data rateDRAM (DDR DRAM), however, transfers data at both edges of the clocksignal (i.e., twice during every cycle of the clock signal), thusdoubling the peak throughput of the memory device as compared withSDRAM. DDR DRAM thus provides a burst of eight data transfers on everyburst read access (when programmed for a burst length of 4). As aresult, the operating speed of the memory can be increased.

Therefore, DDR DRAM offers better performance and lower cost than SDRAM.Furthermore, DDR DRAM offers broader bandwidth than SDRAM, and thehigher operating speed of DDR DRAM is highly applicable to multimediaand entertainment products. With DDR DRAM, the motherboard layout isredesigned and a dual channel type memory slot set is used for insertionof the DDR RAM. The dual channel type memory slot set means that two DDRDRAMs are inserted in a into each memory slot set of a dual in-linememory module (DIMM). The bandwidth of DRAM can be increased to 4.27GB/s due to the dual channel framework effectively increasing theoperational performance. When the primary frequencies of two DDR DIMMsare equal, and the difference between the phases of the two DDR DIMMs is¼ clock cycle, the combined data can be read in one clock cycle.

FIG. 1 is a conventional motherboard 100 with DDR DIMM. The motherboard100 includes a CPU slot 101, a control chipset 102, differential clockgenerator 103, memory slots 104, 105, 106 and 107, terminator circuit108, and terminal resistor 109. The DDR DIMM requires a terminatorcircuit 108 disposed at an end of the arranged memory slots 104, 105,106 and 107 to provide terminator voltage V_(TT) for absorbing thereflecting electric wave. Meanwhile, the receiving data bus of DDR DIMMhas full-up resistors.

FIG. 2 shows the arrangement of a conventional motherboard, wherein thesame symbols are given in FIG. 2 for further description. The serialresistance 110 connects the control chipset 102 and the memory slots104, 105, 106 and 107 as a full-up resistor. The terminator circuit 108is disposed beside the memory slots 104, 105, 106 and 107. The terminalresistor 109, memory slots 104, 105, 106 and 107, and the serialresistance 110 are connected to one terminator voltage V_(TT.)

The memory slots 104 and 106 are a first memory slot set and the memoryslots 105 and 107 are a second memory slot set. The memory slots 104,105, 106 and 107 of the conventional motherboard are alternatelyarranged, hence the distance is increased between two memory slots inone set. Meanwhile, the distance between the terminator circuit 108 andthe memory slot sets is increased, and the distance of the reflectingelectric wave is also increased. Another defect of the terminatorcircuit 108 disposed at an end of the memory slots 104, 105, 106 and 107is that the distance between the control chipset 102 and the memory slotwhich has terminal voltage is increased such that the reflection of theelectric wave is enhanced, and the noise is also increased. Finally, thestability of the DDR DRAM suffers.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a motherboard thatis better than the conventional motherboard.

The motherboard of the present invention includes a printed circuitboard, a first memory slot set, a second memory slot set, and aterminator circuit module. The first memory slot set is disposed on theprinted circuit board and has a first memory slot and a second memoryslot. The second memory slot set is disposed on the printed circuitboard and has a third memory slot and a fourth memory slot. Theterminator circuit module is disposed between the first memory slot setand the second memory slot set. The terminator circuit module iselectrically connected to the first memory slot set and the secondmemory slot set through the printed circuit board.

The terminator circuit module includes a plurality of resistors and aplurality of capacitors, and the resistors and the capacitors areconnected in series.

The resistors and the capacitors are electrically connected in seriesand alternately arranged.

Another object of the invention is to provide a motherboard including acircuit board, a chipset, a first memory slot set, a second memory slotset, a terminal resistor, and a serial resistance. The chipset isdisposed on the circuit board. The first memory slot set is disposed onthe circuit board and has a first memory slot and a second memory slot.The second memory slot set is disposed on the circuit board and has athird memory slot and a fourth memory slot. The terminal resistor isdisposed between the first memory slot set and the second memory slotset. The serial resistance is disposed between the chipset and the firstand the second memory slot sets. The terminal resistor is electricallyconnected to the first memory slot set and the second memory slot setthrough the circuit board. The terminal resistor, the first memory slotset and the second memory slot set are connected to a terminatorvoltage.

The motherboard further includes a plurality of capacitors. The terminalresistor and the plurality of capacitors are alternately arranged.

Another object of the invention is to provide a slot apparatus for amemory module on a printed circuit board. The slot apparatus includes afirst memory slot set, a second memory slot set, a terminal resistor,and a serial resistance. The first memory slot set is disposed on theprinted circuit board and has first and second memory slots. The secondmemory slot set is disposed on the printed circuit board and has a thirdmemory slot and a fourth memory slot. The terminal resistor is disposedbetween the first memory slot set and the second memory slot set. Theserial resistance is disposed on the printed circuit board and iselectrically connected to the first memory slot set and the secondmemory slot set through the printed circuit board. The terminal resistoris respectively and electrically connected to the first memory slot setand the second memory slot set through the printed circuit board. Theterminal resistor, the first memory slot set and the second memory slotset are connected to a terminator voltage.

The slot apparatus further includes a plurality of capacitors, whereinthe terminal resistor and the plurality of capacitors are alternatelyarranged.

The slot apparatus further includes a chipset disposed on the printedcircuit board. The serial resistance is disposed between the chipset andthe first and second memory slot sets.

According to the present invention, the two memory slots in one set arearranged contiguously and a terminator circuit module is disposedtherebetween, and the two memory slot sets are connected to the sameterminator voltage so that the reflection of the electric wavesdecreases when dual channel type DDR DIMM is disposed on themotherboard, and the working voltage is increasing, saving space on themotherboard.

A detailed description is given in the following embodiment withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a schematic diagram showing a conventional motherboard;

FIG. 2 is a schematic diagram showing an arrangement of a conventionalmotherboard;

FIG. 3 is a schematic view showing the present invention;

FIG. 4 is a schematic showing an arrangement of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 shows a schematic view of a motherboard 200 according to thepresent invention. The motherboard 200 includes a CPU slot 201, acontrol chip 202, a differential clock generator 203, a first memoryslot set I, a second memory slot set II, a terminator circuit module208, a plurality of PCI slots 212–214, and a plurality of ISA slots210–211.

The first memory slot set I includes a first memory slot 204 and asecond memory slot 205 for respectively plugging the DDR DRAM in. Thesecond memory slot set II includes a third memory slot 206 and a fourthmemory slot 207 for respectively inserting the DDR DRAM. The terminatorcircuit module 208 includes a plurality of terminal resistors 2081 and aplurality of capacitors 2082. The plurality of terminal resistors 2081and the plurality of capacitors 2082 are electrically connected inseries and alternately arranged.

The CPU slot 201 is for insertion of a CPU. The control chipset 202controls the dual channel type DDR DRAM module. The differential clockgenerator 203 generates the differential clock signal required by thedual channel type DDR DRAM module.

The terminator circuit module 208 is disposed between the first memoryslot set I and the second memory slot set II for completely separatingthe first memory slot set I from the second memory slot set II. The sameset of memory slots is disposed on the same side of the terminatorcircuit module 208. The terminator circuit module 208 providesterminator voltage to the receiving data bus of the first memory slotset I and the second memory slot set II. Additionally, the plurality ofterminal resistors 2081 absorb the electric wave from the data bustransferring line of the DDR DRAM module and decreases the reflectingelectric wave. The capacitors 2082 filter out the high and low frequencynoise to steady the terminator voltage.

FIG. 4 shows the arrangement of the present invention; same symbols aregiven in FIG. 3 for further descriptions. The serial resistance 210connects the control chipset 202, the first memory slot 204 and thesecond memory slot 205 as a pull-up resistor. Another serial resistance210 connects the control chipset 202, the third memory slot 206 and thefourth memory slot 207. The first memory slot set I and the secondmemory slot set II are connected to the control chipset 202 via theindependent paths on the printed circuit board. For example, theindependent paths are respectively disposed on each surface of theprinted circuit board to decrease the distance therebetween. Thisarrangement prevents wasted voltage due to the first memory slot set Ibetween the second memory slot set II and the control chipset 202 as inthe conventional arrangement. The plurality of terminal resistors 2081,the plurality of capacitors 2082, the first memory slot set I, thesecond memory slot set II, and the individual serial resistances 210 areconnected to the terminator circuit module 208 having a terminatorvoltage.

The arrangement of the present invention has the following advantages.More space is made available on the printed circuit board. Theterminator circuit module 208 is disposed between the first memory slotset I and the second memory slot set II to decrease the distancetherebetween. The reflecting electric wave has been decreased and doesnot affect the working voltage. In the terminator circuit module 208,the plurality of capacitors 2082 for filtering noise and the pluralityof terminal resistors 2081 for absorbing the reflecting electric waveare alternately arranged to decrease the ESR of the terminator circuitmodule 208.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited to the disclosed embodiments. To the contrary, it isintended to cover various modifications and similar arrangements (aswould be apparent to those skilled in the art). Therefore, the scope ofthe appended claims should be accorded the broadest interpretation so asto encompass all such modifications and similar arrangements.

1. A motherboard, comprising: a printed circuit board; a first memoryslot set disposed on the printed circuit board having a first memoryslot and a second memory slot; a second memory slot set disposed on theprinted circuit board having a third memory slot and a fourth memoryslot; and a terminator circuit module disposed between the first memoryslot set and the second memory slot set comprising a plurality ofresistors, wherein a terminator voltage is connected to the first memoryslot set, the second memory slot set, and the plurality of resistorsthrough the printed circuit board.
 2. The motherboard as claimed inclaim 1, wherein the terminator circuit module further comprises aplurality of capacitors, and the plurality of resistors and theplurality of capacitors are connected in series.
 3. The motherboard asclaimed in claim 1, wherein the first, second, third and fourth memoryslot are used for plugging in a memory device.
 4. The motherboard asclaimed in claim 2, wherein the plurality of resistors and the pluralityof capacitors are electrically connected in series and alternatelyarranged.
 5. A motherboard, comprising: a circuit board; a chipsetdisposed on the circuit board; a first memory slot set disposed on thecircuit board having a first memory slot and a second memory slot; asecond memory slot set disposed on the circuit board having a thirdmemory slot and a fourth memory slot; a plurality of terminal resistorsdisposed between the first memory slot set and the second memory slotset; and a serial resistance disposed between the chipset and the firstand the second memory slot sets, wherein the plurality of terminalresistors is electrically connected to the first memory slot set and thesecond memory slot set through the circuit board, and the plurality ofterminal resistors, the first memory slot set and the second memory slotset are connected to a terminator voltage.
 6. The motherboard as claimedin claim 5, further comprising a plurality of capacitors, wherein theplurality of terminal resistors and the plurality of capacitors arealternately arranged.
 7. A slot apparatus for a memory module on aprinted circuit board, comprising: a first memory slot set disposed onthe printed circuit board having a first memory slot and a second memoryslot; a second memory slot set disposed on the printed circuit boardhaving a third memory slot and a fourth memory slot; a plurality ofterminal resistors disposed between the first memory slot set and thesecond memory slot set; and a serial resistance disposed on the printedcircuit board and electrically connected to the first memory slot setand the second memory slot set through the printed circuit board,wherein the plurality of terminal resistors are respectively andelectrically connected to the first memory slot set and the secondmemory slot set through the printed circuit board, and the terminalresistors, the first memory slot set and the second memory slot set areconnected to a terminator voltage.
 8. The slot apparatus for a memorymodule as claimed in claim 7, further comprising a plurality ofcapacitors, wherein the plurality of terminal resistors and theplurality of capacitors are alternately arranged.
 9. The slot apparatusfor a memory module as claimed in claim 7, wherein the printed circuitboard is a motherboard.
 10. The slot apparatus for a memory module asclaimed in claim 9, further comprising a chipset disposed on the printedcircuit board, wherein the serial resistance disposed between thechipset and the first and the second memory slot sets.